Despite the demographic imperative of a rapidly growing older US population, increasing life expectancy, and rising cancer rates with advancing age, there is a paucity of research on older (65+ years) survivors. This project leverages NCI's investment in an extant cohort of older women with breast cancer to address new scientific questions about survivorship care. In this study, we use the Institute of Medicine's (IOM) framework based on Donadebian's model of structure, process and outcomes to determine who cares for this cohort of older survivors after active treatment ends and how the type of provider affects quality of care. The cohort includes 1100 older English and Spanish speaking breast cancer patients with detailed baseline data. Women were diagnosed between late 2005 and 2007 in 106 Cancer and Leukemia Group B (CALGB) institutions; 90% of the sites are in community settings. The cohort is representative of the US population of breast cancer patients in terms of race/ethnicity, insurance coverage and community settings of care; half would be considered low SES based on education and one-third live in areas of high poverty. Our multidisciplinary team will conduct annual telephone follow-up interviews over five years post active-treatment to examine care choices and experiences, symptoms, quality of life and satisfaction. These data will be linked to Medicare claims from the 18 months prior to five years post-active treatment to define baseline patterns and post- treatment providers and services. We will also use AMA files to obtain physician characteristics (specialty, gender, and race) and survivor's addresses to include census data on area characteristics. Our primary outcomes will be rates of services from claims (e.g., cumulative use of mammography among survivors) and patient-rated satisfaction and quality of life. The key predictor is model of survivorship care (shared by an oncologist and primary care provider or a primary care provider alone); we will assess whether communication and/or coordination mediate outcomes. Finally, we will conduct in-depth, open ended interviews among a sub- set of minority and non-minority women each year to enhance our ability to understand whether there are race/ethnicity differences in care. The use of an established cohort allows us to collect new data in a cost- efficient manner; this research also addresses a key priority for survivorship research as articulated by the IOM. Patterns of care that maximize quality of life and functioning are particularly salient in older women, where declines may exacerbate frailty and ability to live independently. We will use project data to guide future interventions to improve outcomes and inform clinical practice and policy decisions about care models that maximize quality for the growing older population of breast cancer survivors. Despite the demographic imperative of a rapidly growing older US population there is a paucity of research on older (65+ years) survivors. This project will examine whether care in the first five years after active treatment ends that is shared by an oncologist and primary care physician results in better quality care, satisfaction and quality of life for older survivors than care provided by a primary care physician alone. Results will be used to guide future interventions to improve outcomes and inform clinical practice and policy decisions about care models that maximize quality for the growing older population of breast cancer survivors. Patterns of care that maximize quality of life and functioning are particularly salient in older women, where declines may exacerbate frailty and ability to live independently.